Understanding Wheel Drive: All, Four, Front, Rear
We’ve all been there. You’re in the middle of the Mojave Desert, decked head to toe in designer leather, waiting for the man in the hockey mask to finish explaining the rules of a death race. The stakes are high, but you’ve seen Mad Max with Director Commentary on Blu Ray like, five times, so you’re feeling pretty good about your chances. The flag drops, and a plume of dust and sand fills the air as the racers shoot off from the starting line. Something is wrong. Your opponent’s vehicles are becoming increasingly smaller blips on the horizon as you fall further into last place. How could this be? Should you have put more spikes on the exterior? Did you forget to fill the NOS canister? Or, could it be that you made the wrong choice in selecting a Dodge Magnum to aid you in your bid to become Road King of the American Southwest? While one could argue that you can never have enough spikes on your car in a death race, the real problem lies in the fact that you put your faith, and the last of your water rations, into using a rear-wheel drive vehicle. If only you had known the distinguishing factors that separate Front-, Rear-, 4-, and All-Wheel Drive. However, seeing as how Desert Raiders have taken your ride as their just reward, it would seem you have the free time now, so let’s get you up to date in the hopes of giving you a fighting chance down the road.
Currently, FWD dominates the auto landscape, powering vehicles as small as subcompact hatchbacks to full-size SUVs. FWD’s rise in commonality has occurred over the last 30-some years as the industry has shifted away from RWD, the previous industry standard. FWD offers numerous benefits, including a more balanced weight distribution, better handling/grip in adverse driving conditions, and FWD vehicles are generally easier to service. In addition, front-powered vehicles are efficient. They enjoy an improved fuel economy and allow for companies to make smaller/lighter models which decreases the overall waste that occurs in the production of a vehicle (because the weight of the engine and transmission is directly over the driven wheels) while also limiting the required power necessary to turn the vehicle. The downsides of FWD revolve around the fact that these vehicles typically don’t have an even weight distribution (with most of the weight being found on the front end), which can lead to increased wear and tire on the front tires. Some drivers will note that the FWD category also possesses significantly less “enthusiast” cars, with a severely reduced choice of engine options, so exhibitionists may want to steer clear.
- Acura MDX
- Buick LaCrosse
- Ford Focus
- Honda Civic
- Mazda CX-5
- Nissan Altima
- Toyota Camry
- Volkswagen Golf
Rear-Wheel Drive was the most common form of engine/transmission used in automobiles throughout the 20th century. The lion’s share of RWD vehicles use a longitudinally-mounted engine in the front of the vehicle, operating the rear wheels through a driveshaft linked by a differential between rear axles. RWD has fallen in popularity as of late, due to its higher production costs and a growing belief from customers that FWD is the safer option, performing better on slippery roads. However, RWD still possesses many benefits for the right situations. RWD vehicles handle better in dry conditions, as less force is applied to the front wheels, allowing for more friction to be used in steering the vehicle while letting more power be applied through the rear wheels. RWD vehicles also generally have a more even weight distribution, further increasing the overall handling. Keep in mind, however, that RWD vehicle do typically have a higher purchase point due to their more complicated assembly.
Most modern 4WD systems are only on when you activate them. This is typically achieved electronically or by pulling the lever that rests somewhere in the front of your vehicle. 4WD enjoys the benefits of being able to handle low speeds in snow or mud while also boasting the drivability of two-wheel drive in normal conditions. In essence, this leads to less fuel consumption, as when left in 2WD, there are less moving parts and, as a result, less restrictions to push the vehicle forward. 4WD provides the best traction in off-road conditions, and is considered to possess the most proven, adaptable technology. However, both the weight and price of the car increase when it is 4WD, so be sure your wallet and your brain are ready.
- Chevrolet Tahoe
- GMC Canyon
- Honda Pilot
- Jeep Cherokee
- Lincoln Navigator
- Mitsubishi Lancer
- Ram 1500
- Toyota 4Runner
All-Wheel Drive is the most recent innovation and, as such, is an entirely more complicated beast. Some like to explain the difference between 4WD and AWD as the difference between a ‘car’ system (AWD) and a ‘truck system’ (4WD). There are two different types of AWD, mechanical and electronic. Mechanical-AWD relies upon three differentials. A single differential is a box of gears that takes power from the transmission and breaks it down at different levels between two wheels or the front and rear axles. This system works to get the most traction to power the wheels by dividing power between the front and rear axles via the center differential, or the individual wheels through the front and rear differentials. Still, AWD isn’t as intricate as 4WD and, as a result, can’t match the same levels of traction in low-speed, off-road situations. Most current AWD vehicles are operated via computing systems within the ride, using wheel sensors to monitor, traction, speed, and numerous other data points in a split second. This engine control unit determines where power is sent and which specific wheel it is sent to based on the current level of tire grip.
So there you have it, you now know the basics of what makes each drivetrain system unique. Take this knowledge and use it to reclaim your rightful throne atop the pantheon of road warriors. Or at least get third place. I mean, come on.
FWD, RWD, 4WD, or AWD – which do you prefer? Let us know in the comments!